A presente dissertação apresenta o estudo de estruturas reticuladas planas, também chamadas de treliças. A grande demanda da construção civil, e projetos cada vez mais arrojados motivaram esta pesquisa. Foram realizados três modelos de treliças, com o intuito de comparar o problema estático em relação ao problema dinâmico e verificar qual a influência dos esforços nas juntas tipo K das treliças. As juntas das treliças foram utilizadas para analisar a região plastificada e a tensão (von-Mises). As rotinas de cálculo para obtenção dos resultados, foram implementadas no software Matlab®, para o problema estático e os resultados foram comparados entre o software FEM-Reticulado2D do Matlab e software comercial onde as diferenças ficaram em menos de um por cento. No problema dinâmico foi adicionado amortecimento, estando mais próximo de uma estrutura real. Para este caso foi utilizado o amortecimento de Rayleigh, que é encontrado por meio da frequência natural e o método utilizado para integração no tempo foi o método de Newmark. A frequência natural também foi obtida por meio de formulações implementadas no Matlab. A região de plasticidade e a tensão (von-Mises) nos nós foram obtidas com auxílio do software Ansys. Tendo em vista os resultados, pode-se concluir que o problema dinâmico por levar em consideração a influência das forças de inércia, resultou em esforços maiores em relação ao problema estático. Verificou-se que quanto mais esbelta for a estrutura, menor será a frequência natural da mesma, por isso, deve-se tomar cuidado para que estruturas esbeltas não venham a absorver energia de ações externas como o vento e entrarem no efeito de ressonância. A plasticidade e a tensão (von-Mises) dependem da intensidade das forças e das propriedades geométricas e físicas do perfil utilizado. / This thesis presents the study of plane frame structures, also called trusses. The great demand of construction, and projects increasingly bold motivated this research. Three models lattices were performed in order to compare the static problems concerning dynamic problem and check the influence of the joints efforts K type of truss. The joints of the truss were used to analyze the plasticized region and the stress (Von-Mises). The calculation routine for obtaining the results were implemented in Matlab software for the static problem and the results were compared with the FEM-Reticulado2D Matlab software and commercial software where the differences were less than one percent. In the dynamic damper problem was added, being closest to an actual structure. For this case we used the Rayleigh damping, which is found by means of the natural frequency and the method used for time integration method is the Newmark. The natural frequency was also obtained by formulations implemented in Matlab. The plasticity of the region and the tension (von Mises-) nodes were obtained with the help of Ansys software. Considering the results, it can be concluded that the dynamic problem by taking into account the influence of forces of inertia resulting in increased efforts in relation to the static problem. It was found that the more slender for the structure, the lower the natural frequency of the same, so one must be careful that slender structures will not absorb energy from external actions like wind and entering the resonance effect. The plasticity and the stress (Von-Mises) depend on the intensity of the forces and the geometrical and physical properties of the used profile.

Please read the abstract in the section 00front of this document / Dissertation (MEng (Mechanical Engineering))--University of Pretoria, 2007. / Mechanical and Aeronautical Engineering / MEng / unrestricted

Orientadores: Newton de Oliveira Pinto Júnior, João Alberto Venegas Requena / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-22T02:16:45Z (GMT). No. of bitstreams: 1 Silva_AugustoOttoniBuenoda_D.pdf: 10620003 bytes, checksum: 1ae2a0949d644fd7b3bdbee6ccba8b20 (MD5) Previous issue date: 2013 / Resumo: As treliças mistas em aço-concreto, alternativas bastante eficientes para vencer grandes vãos, são geralmente empregadas em edifícios comerciais e industriais, e, em pontes ferroviárias e rodoviárias. Em muitos casos, para que se possibilite a passagem de dutos, dificultada nos quadros com presença de diagonais, e construído um painel Vierendeel central; porem, em algumas situações, este único painel pode ser insuficiente, necessitando-se então a criação de novos painéis para satisfazer o uso que se pretende dar a construção. Neste sentido, o objetivo do estudo foi determinar através de um procedimento de calculo analítico e modelagens elástica bi-dimensional e plástica tri-dimensional, a capacidade resistente e o modo de ruptura de uma treliça tubular mista bi-apoiados com 15 metros de vão, sendo todo o terço central constituído por painéis Vierendeel. Em seguida, mantendo-se o vão de 15 metros e os perfis estipulados no dimensionamento, foi feita uma parametrização dos resultados para estruturas com 3, 7, 9 e 13 painéis. O estudo, desenvolvido para cargas de escritório, apontou a proporção vão/3 - vão/3 - vão/3 como a ideal para a relação entre trechos treliçado - Vierendeel - treliçado, pois ao se aumentar a proporção do trecho central ocupado pelos painéis Vierendeel, os novos sistemas perdem muita rigidez passando a não suportar mais a carga estipulada no projeto. Alem disso, podem passar a apresentar deslocamentos verticais excessivos e resistência às forcas cortantes externas atuantes sobre os painéis insuficiente / Abstract: The steel-concrete composite trusses, an efficient alternative to overcome large spans, are generally used in commercial and industrial buildings, and rail and road bridges. In many cases, in order to enable the passage of ducts, with complications in the frames with the presence of diagonals, a central Vierendeel panel is built, but in some situations, if this single panel may be insufficient, then one would need to create new panels to meet the intended use to build. In this case, the objective of the study was to determine, through analytical calculation, two-dimensional elastic modeling and three-dimensional plastic modeling, the bearing capacity and failure mode of a bi-supported truss with a 15 meter span, and the entire central third consisting of Vierendeel panels. Then, keeping the span of 15 meters and the sections determined in the design, a parameterization of the results was made for structures having 3, 7, 9 and 13 panels. The study developed for office loads, found the proportion span/3 - span/3 - span/3, as the ideal relationship for the truss - Vierendeel - truss lengths, because by increasing the proportion of the length occupied by the central Vierendeel panels, the new system loses stiffness and no longer support the load stipulated in the project. Furthermore, they can start presenting excessive vertical displacements and insufficient resistance to external shear forces acting on the panels / Doutorado / Estruturas / Doutor em Engenharia Civil

The aim of this thesis is design and assessment of the steel structure of the multi-storey administration center in Martin. Floor plan dimensions are in the shape of a square 40 x 40 m. Column spacing is 8mx8x. Building has 6 floors and total height is 22,2m. Floor and roof structure is made of steel-concrete composite slab . Part of the work is analyze two different versions. Version A has longitudinal rigidity due to truss bracing. Rigidity of Version B has is ensured by frame conections between beams and columns.Version A was selected as better solution. All parts, except truss braicing is made of rolled beams. The whole structure is made of steel S355.

Item of Master´s thesis is to design, review and compare two variants of steel structures production hall with overhead crane with load capacity 25t. One variant is frame construction and second one is construction with trusses. Layout dimensions is 45m x 60m and the height of the ridge is 10m. Stability is provided by wall and roof bracings. Building is sheathed. Structures is situated in Frýdek - Místek.

The following project work studies trusses and roof structures and their performance during a fire in terms of rules and requirements that needs to be considered. Determination of how resistant truss or roof construction is still heavily dependent on the subjective experience and assessment of professional. It means that nowadays stages of this defining of fire resistance of roof/truss are still in need of clarification. The load combination for accidental load is compared to the ultimate limit state during the fire and it was showed that the loads were lower. The strength of timber during the fire was calculated by the two methods. Calculations by both methods revealed that timber used in construction can withstand fire by 0 minutes. However, fire resistance of the wooden materials can be improved by different techniques that were described in this study. The biggest improvement of fire resistance can be achieved with the help of covering - gypsum boards and rockwool, or even with wooden covering if lower protection is needed. As well, many fire-retardant treatments were developed that can improve wood performance during fire by slowing down the spread of fire, by limiting the building up of smoke and other volatiles. Instead of fire-retardant treatment fire retardant paints can be used too. This study showed stages of establishing fire requirements of wooden roof structures by two examples. In this study, two calculations were performed for two different house types, a family house, and an apartment building, to compare the difference between normal load dimensioning and fire load dimensioning. In the fire load dimensioning method, two different times were considered - R30 and R60 load capacity. When calculating the normal load dimensioning, it has been shown that an unprotected truss has no fire resistance, and that the truss has a fire resistance, with respect to bearing capacity, which corresponds to R0, which means that it must be protected for the required time. / Samhällsbyggnad / Husbyggnad / Konstruktion

The post-buckled performance of cross-braced single angles was experimentally determined. The results of this study will be used by the Bonneville Power Administration for the analysis of member performance in transmission towers.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1980. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Vita. / Includes bibliographical references. / by Pierre Hernando Montauban. / M.S.

Hagastaden is a new district in Stockholm that is growing, and many structures are being built. Kv Forskaren, a funnel-like office building, will be built above the Haga tunnel in an ongoing project. During the design phase, where Bjerking AB carried out the construction design, it has been concluded that heavy concrete beams or steel trusses need to be placed over the tunnel that will lead the loads to the massive tunnel walls from the intended building above. In 2016, the Swedish construction and real estate sector released 21 million tonnes of greenhouse gases. This is an increase of 2 million tonnes in comparison from the previous year. Since the choice of construction material is strongly linked to the environmental impact, it is extremely important to choose the material that contributes to least emissions. In order to determine which construction material, concrete or steel, from an environmental perspective is the most suitable to use, a simplified LCA for each material was performed. The study was based on processes that are in the production phase. Environmental indicators that were studied and compared were carbon dioxide equivalents, CO2-e. Furthermore, the purpose was also to compare costs for the manufacturing of the materials. In addition to these factors, an overall assessment was also considered, such as maintenance and fire protection. To be able to make a simplified LCA, the program Construction's environmental calculation tool, BM, was used. Before using the tool, calculations of the material quantities were made based on given drawings on Forskaren from Bjerking. In order to determine which design type is preferable in a holistic perspective, a literature study was also done. The LCA study showed that the steel trusses contributed the least emissions of carbon dioxide equivalents during the production phase. Based on the work done, it has been established that there are both advantages and disadvantages to the construction materials. An active choice of one of these must be based on the specific conditions and requirements that exist in a project. / Hagastaden är en ny stadsdel i Stockholm som växer och många konstruktioner tillkommer. Kv Forskaren, en trattliknande kontorsbyggnad ska byggas ovanför Hagatunneln i ett pågående projekt. Under projekteringens förskede, där Bjerking AB utfört konstruktionsprojekteringen, har man dragit slutsatsen att kraftiga betongbalkar eller stålfackverk behöver placeras över tunneln som ska leda lasterna till de massiva tunnelväggarna från den tänkta byggnationen ovanför. Den svenska bygg- och fastighetssektorn släppte år 2016 ut 21 miljoner ton växthusgaser. Detta är en ökning med 2 miljoner ton jämfört med föregående år. Eftersom valet av konstruktionsmaterial är starkt kopplat till miljöpåverkan är det ytterst viktigt att välja det som bidrar med minst utsläpp. För att avgöra vilket konstruktionsmaterial, betong eller stål, ur ett miljöperspektiv är lämpligast att använda utfördes en förenklad LCA för respektive material. Studien utgick från processer som är i produktionsfasen. Miljöindikatorer som studerades och jämfördes var koldioxidekvivalenter, CO2-e. Vidare var syftet också att jämföra kostnader för tillverkning av materialen. Utöver dessa faktorer gjordes även en helhetsbedömning där aspekter som underhåll och brandskydd beaktades. För att kunna göra den förenklade LCA-studien har verktyget Byggsektorns miljöberäkningsverktyg, BM, använts. Innan verktyget användes gjordes en mängdberäkning utifrån givna ritningar på Kv Forskaren från Bjerking. För att kunna avgöra vilken konstruktionstyp som är att föredra i ett helhetsperspektiv gjordes även en litteraturstudie. LCA-studien visade att stålfackverken bidrog med minst utsläpp av koldioxidekvivalenter under produktionsfasen. Utifrån arbetet som gjorts har det kunnat fastställas att det finns både för- och nackdelar hos konstruktionsmaterialen. Vid ett aktivt val av något av dessa måste man utgå från de specifika förutsättningar och krav som förekommer i ett projekt.

This thesis presents a research project aimed at advancing the treatment of cold-formed steel (CFS) structural reliability in roof trusses. Structural design today relies almost exclusively on component-level design, so structural safety is assured by limiting the probability of failure of individual components. Reliability of the entire system is typically not assessed, so in a worst-case scenario the system reliability may be less than the component reliability, or in a best-case scenario the system reliability may be much greater than the component reliability. A roof truss itself, is a subsystem with several possible failure modes that are being studied in this test program. These trusses are constructed of CFS members that nest with one another at the truss nodes and are connected by drilling fasteners through the mated surfaces, as well as having steel sheathing fastened to the top chords for lateral bracing. Presented in this paper is a series of full-scale static tests on single cold-formed steel roof trusses with a unique experimental setup. The test specimens were carefully monitored to address multiple failure modes: buckling of the top chord, buckling of the truss webs, and any connection failures. This research includes the experimental results, the computed system reliability of the trusses as well as their relationship between the components reliability.